The two pals are in the 30-man squad which will later be trimmed to 23. De Gea was voted the player of the season for the club, while Mata has been slightly inconsistent but still shown glimpses of magic since signing from Chelsea in January.
Mata is quite an interesting one - although he is in a way the type of player the Spanish ranks are full of, at the same time they don't really have anything exactly like him in terms of being a purely creative player who likes to sit in the hole, so he could be kept on as one of their best options even instead of players who have probably had better seasons.
Nonetheless, it's nice to see that we've still got a couple of players playing for the World Champions. Hopefully De Gea can continue to impress.